It is not a good idea to try to refer newsgroup users to a previous post.
News servers and news readers, in various combinations, can be rather
unreliable -- a given reader may not even see the original post. But, even
more so, few users have the time and energy to search out a previous post.
Many "filter" on the Subject and only open those whose subject seems to
indicate a post they can or are willing to help with. It's not that they are
lazy, it's just a matter of time and energy "coming at a premium".